1. Field of the Invention
The present invention generally relates to an expansion module, in particular, to a projection system and an expansion module adapted to a projector.
2. Description of Related Art
Projection devices may project an image onto a large screen to facilitate more people to watch the content displayed on the screen at the same time, and projection devices are applied in public, such as in companies and schools. Further, with the trend that home display products are developed towards the direction of large size, projection devices are gradually popularized in common families, and become a common electronic product in modern life.
Furthermore, with the progress of the technology, various electronic products are developed towards the trend of high speed, high performance, and being light, thin, short, and small. In this trend, portable pico projectors (or mini projectors) have become the mainstream of the personal digital market in the future. Generally, the light source of the pico projector is a light emitting diode (LED) or other solid state light source, so as to improve the total luminance, and improve the brightness of the projected image. After being manufactured into the final product, the size of the battery included in the pico projector is approximately similar to that of the common mobile phones available in the market. The pico projectors are light, thin, short, and small, and are portable, and may be used in any places. Further, it is expected that the battery of the pico projector may provide electrical power for several hours, and therefore when being used for entertainment, the electrical power provided by the battery is enough to meet general demands, for example, watching a DVD movie of about 150 minutes. In business uses, the pico projector may project a picture of 2-100 inches according to the demands of the conference briefing.
For projector manufacturers, especially for original design manufacturer (ODM) plants, there are some inconveniences during the projector development process. FIG. 1 is a flow chart of a projector development process. Referring to FIG. 1, when developing a new type of projector, the manufacturer first carries out a plan proposal for the specification of the new type of projector (Step S10), so as to determine the specification of the projector. Next, relevant persons or customers may evaluate whether the specification of the proposed projector meets the requirements or not (Step S12). If the specification does not meet the requirements or needs to be modified, the specification proposal is rejected to the proposal persons for modification. If the specification meets the requirements, the specification proposal is given to industrial designers (IDs) to perform the appearance design of the projector (Step S14). Then, the relevant persons or customers evaluate whether the designed appearance of the projector is required to be changed or not (Step S16). If the appearance is required to be changed, the original appearance is rejected to the ID for changing. If the appearance is not required to be changed, a mockup may be manufactured according to the designed appearance and the subsequent step of opening mode may be performed (Step S18).
However, after opening mode, if the specification or the appearance design of the projector is required to be changed, an expensive cost should be paid for making the mechanism mold again, so as to be undoubtedly a cost burden for the manufacturer, and reduce the will to change the design.
Further, when buying a projector, a consumer may choose the projector with the suitable input specification and the suitable output specification as a main consideration. In this situation, the appearance of the projector becomes a secondary consideration for purchase instead. Therefore, when being attracted by the appearance of the projector, if the projector does not provide an interface suitable for the consumer's own input/output specification, the consumer may give up the ideal projector to choose the projector with other appearances. For example, FIG. 2 and FIG. 3 show two projectors 50 and 60 having different input port combinations respectively. The input port of the projector 50 includes a universal serial bus (USB) interface 52, a video graphics array (VGA) interface 54, a high-definition multimedia interface (HDMI) 56, an S-video interface 58, and a RCA interface 62. The input port of the projector 60 includes a digital visual interface (DVI) 64, a VGA interface 54, an HDMI 56, an S-video interface 58, and a RCA interface 62. When a consumer chooses a projector (for example, the projector 60) having DVI input interface due to the limit of the display card of the personal computer thereof, if the consumer prefers the appearance of the projector 50 in fact, the consumer may give up purchasing the projector 50 without the DVI input interface. However, the expected sale purpose may not be achieved in such a case for manufacturers who take special appearance or series appearance as the main marketing tactics.